1. Field of the Invention
The present invention relates to a pencil sharpener, and more particularly to an adjustable pencil sharpener having capabilities of adjusting degrees of sharpness of a pencil tip and providing a user with a clear signal when the adjusting process is completed.
2. Description of Related Art
A pencil sharpener can sharpen a pencil to expose and sharpen the pencil core for writing. To fit with different needs, an adjustable pencil sharpener is provided to adjust degrees of sharpness of pencil tips. With reference to FIG. 7, a conventional pencil sharpener disclosed in Taiwan Utility Model No. M384109, entitled “Pencil Lead Sharpener Having Two Operation Stages”, comprises a waste case 70, a first blade base 71, a second blade base 72, a cam 73 and a rotating board 74. The first blade base 71, the second blade base 72 and the cam 73 are mounted in the waste case 70. The second blade base 72 is mounted on and axially moveable relative to a bottom of the first blade base 71. The cam 73 has multiple pushing protrusions 731 in different longitudinal heights formed on and protruding from a top of the cam 73, and the second blade base 72 has a bottom abutting one of the pushing protrusions 731 on the cam 73. The rotating board 74 is mounted on and exposed from a bottom of the waste case 70 and is connected with the cam 73. When the rotating board 74 is rotated, the cam 73 can be rotated to push the second blade base 72 to move axially relative to the first blade base 71. Accordingly, the relative axial distance between the first and second blade bases 71,72 can be changed, and the tip of the pencil can be sharpened into varying degrees of sharpness.
However, the conventional pencil sharpener has the following drawback. When the rotating board 74 is rotating to adjust the sharpness of the pencil tips, the conventional pencil sharpener cannot provide the user with a clear feedback signal to show that the adjusting process is completed by positioning the blade bases 71,72. The rotating board 74 may be over-rotated or the user gests confused about the direction in which the rotating board 74 should be rotated, so the conventional pencil sharpener is inconvenient in use.
To overcome the shortcomings, the present invention tends to provide a pencil sharpener to mitigate or obviate the aforementioned problems.